Interference and static eliminator



E. C. RAASCH INTERFERENCE AND STATIC ELIMINATOR Oct. 9, 1928. v 1,686,878

Filed March so, 1927 INVENTOR BY 9M ATTORNEYS Patented Oct. 9, 1928. v

f vu NITED TATES TE T],o HcE.

riann -RAAscH, or wAtrPr N, WISCONSIN. I

m'rnnrnnnivcnjnnn STATIC ELIMIN-aroiz.

Application filed March 30, 1927. Serial N6. 179,512. i

This inventionrelates to improvements in interference and static eliminators, particularly adapted for use with radio receivmg sets.

vention to provide an, interference and static eliminator adapted to be connected ln the 216I1Etll62tCl-1I1'W1IG ad acent a radio'recelver and which will efiectively reduce .andeliminate static and interference received ;by the radio set. 1 1

A further object of the lnventionis to provide an interference and static eliminator .which absorbs static and interference before it'reaches the receiver. I e f A further object of the invention is to provide a device of the character described, which when attached with'a radio receiver,

will result in the reception of music and talking natural in quality and unmarred by atmospheric disturbances.

A further object of the invention is to provide a device of the character described which can be manually adjusted so as to be readily adapted to the peculiar receptive qualities of any radio receiver.

A further object of the invention is to provide a device of the character described which can be adjusted so that it is possibleto separate stations that are crowded onthe dials of a radio receiver.

A further object of the inventlon is to provide a device of the character described which will .result in a saving in the life of B and C batteries usedyby a radio.

receiver.

A further object of the invention is to provide a device of the character described which can be readily attached to the rear portion "of a radio receiver in a convenient out-of-the-way position.

A further object of the invention is to pro-' It is the primary object of the present in ,Fig. lis'a .vertical sectional view of the interference and static eliminator;

Fig. 2 is a plan view thereof withthe cover shown in horizontal section; and J Fig; 3 isza front-end view thereof with thecover in raised position.

Referring now' more particularly to the drawings, it will appear that the numeral 5 indicates'the base ofthe device which is'of a flat, rectangular shape and is 1 preferably 7 formed -of wood, composition, rubber or other non-conducting material. Metallic blocks 6 and 7 are secured to the face of-the base near the ends thereof and the outer end portion ofan elongated resistance member 8 .entersan aperture 9 in the block 6 and is secured therein by a set screw 10. The outer end portion of the resistance member is angular inshape, as at 11, forming a supporting bracket portion, and, said resistance member enters an aperture in the closed rear end portion of a cone member 12 formed of non-conducting material, supporting said end portion of the 'cone member. The bracket portion 11 of the resistance member is anchored to the base 5 by an eyed screw 13 .andthe cone member is connected to the resistance member by a-"collar 14 anda set,

screw: 15.

Said resistance member 8 is preferably formed of twelve gauge copper wire and the major portion thereof within the confines of the cone member is formed inconvolutions or coils, as at 16.

Within the forward open end portion of the cone member a metallic washer 17 is lodged and said washer engages the surface of a thin disc 18 of celluloid, said disc being confined between the washer and the periphery of a. small inner metallic cone 19.

The apex of the innercone 19 is apertured, as at 20, to permit the entrance of the outer elongated portion 21 of the resistance member and the end of, saidportion 21 is pointed, as at'22, and extends through a central aperture in the disc 18,-terminating slightly beyond the outer face thereof, as shown in Fig.1." V f 1 A wire or'connection 23 extends into an aperture 24 in the other metallic block 7- and is held therein by a set screw 25. The

medial portion of said connection 23 ex- 1 tends through an eyed screw 26 secured in the base 5 and then is bent upwardly and is connected with a metallic finger 27. Said finger 27 extends through a slot 28 therefor in the cone 1'2 and is mounted? against a at block 29 positioned within a split portion of the Washer 17. The finger is yield-able and the free end portion ofthe same, ad-

jacent the pointed end portion 22' of the re sistance member, may-be flexed. V p For the purpose of flexing the finger 27 to adjust the space between it andthe resistance member 8, an elongated. adjusting screw 30- is provided, threaded through a U-bracket 31 secured to the sides of the open end portion of the cone member 12. The outer end portion of thead'gjusting screw is formed with a knur-lcdhead :32, while the inner end portion engages the flexible part of the finger 27 to tom-cc itinto proximity .to"the-resistance" member end 22.

The cone member 12 iscen'closed or housed hy a Cover member hinged at: its rear cndsportion to the: base 5. and it is held in enclosing position by complementary catches 3% and 351. 'l hezcover may, alsobe opened to -the position shown in Fig. 3, permitting access to the cone member. The forward and rear portions of the'cover are slotted, as at 36 and-8 7, 'toaccommodate extending portionsof the devicev In use,,the device is preferably positioned against therear wall oi? a radio receiver and the end portion oi the aerial lead in wire 38 is inserted and clamped into the metallic bloclrti Another wire 39 is connected to the block 7 and said wire is attached to the aerial terminal ot the receiver; It will'thus :be that the device is included in the aerial circuit-.- The coiled portion within the cone member in effect forms a choke, while the small metallic cone engaged by the endof the choke, together with the celluloid disc andvmetallic washer, forms a condenserwhich is adjustable by means of the Sound waves pass through the aerial wire and into the choke portion and to the metallic cone. An induced current is set up in- .the other'side' ozfi the condenser includin-g'the metallic washer and finger and said current is led to therecei-ver through the wire 89. This arrangement effectively reduces static, interference and atmospheric disturbances and lengthens the life of the batteries v Fromthe foregoing description it will be seen; that the improved interference and static eliminator is of sil nple novel cons struct-ion, and is well adapted for the purposes; described. What I claim as my invention is:

1. The combination with aradio receiver including an" aerial circuit, of art interfeia ence eliminating device interposed in said circuit and comprising in series a choke member and a condenser member, a conical insulating'housing enclosing said members,

acond-enseradjusting member projecting from theconical housing. 7

2. An interference eliminating device, comprising an insulating housing, a coil 'icnewvirthin, a manneineanher' within the honsing I coil, a sheet 'o lf non-conducting material across vthe metallic member, a metallic ring separated from the metallic member by said 'non condu'ctingt sheet, one end portion of the coil extending through the metallic member and the non-conducting :sheet, a

finger enga ngzthe ring and spaced from adjacent one" end portion of the the extended endportion of the-coil, and

circuit connections connected to the other end portion otthe coil and to the fingers.

4 3. Air interference xehnainatmg device comprising an insulating housing, dished metallic member Within one end-" portion thereof, non-conducting. disc covering the end of said dished member, a metallic rl ng spaced from the dished member by said :d-isc,

a coil within the'lroaising and having a projecting end portion extending through said dished member and said disc, a yielding finger engaging the and spaced from the'extended endportion out the coil, means for manually moving said finger to vary its proximity to the: end portion of the coil, and circuit Wires extending from the opposite end portion of the coil and from the'finger. i. inteiafienence eliminating device,

comprising a base member, an insulating housing supported t'lreneabove, a conical metallic member within one end portion of the housing, non-conducting disc covering the open end oi said conical member, a metallic ring spaced from the conical memher by said disc; a coil within the housing and having a projecting end portion extending; through sa conical member and the genengaging the rmg'and RAASGHE, 

